#include "stm32f10x.h"                  // Device header

void Timer_Init(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_InternalClockConfig(TIM2);

    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitstructure;
    TIM_TimeBaseInitstructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitstructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitstructure.TIM_Period = 10000 - 1;  // maximum
    TIM_TimeBaseInitstructure.TIM_Prescaler = 7200 - 1; //pre division
    TIM_TimeBaseInitstructure.TIM_RepetitionCounter = 0; //only applays to NB Timer(Tim1 and Tim8 in APB2)
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitstructure); /*已初始化就进入中断原因 Generate an update event to reload the Prescaler and the Repetition counter values immediately */
    TIM_ClearFlag(TIM2, TIM_FLAG_Update); //clear 更新flag to 避免马上进入更新中断

    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
    NVIC_Init(&NVIC_InitStructure);

    TIM_Cmd(TIM2, ENABLE);

}

/* IT templete
void TIM2_IRQHandler(void)
{
    if (TIM_GetFlagStatus(TIM2, TIM_FLAG_Update) == SET)
    {

        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    }
}
*/
